Changing the size of my chainrings?

[XmisterIS]

I currently ride with 34/50.

I find that I never use the lowest gear (34 ring with the chain on the biggest sprocket). Conversely, when I'm booting down a hill, I find that I run out of gear!

I would like to go bigger ... what kind of size and ratio would be good?

I notice that you can get 39/53 quite easily ... how much more gear would that actually give me on the top end?

Would it be sensible to go really huge and use a 56? If so, what size of smaller ring should I put with a 56?

Or is 56 too big?

Will I need a longer chain?

For example, I could make up a 39/53 with a couple of these: http://www.chainreactioncycles.com/Models.aspx?ModelID=35784

I dunno, I dunno! Help! Help!

 

[Joe24]

Can you not cut your existing chain ring, then open it up and add a section in?

 

[XmisterIS]

Whut??? I don't understand ... you mean actually cut the solid metal, unbend it and put more teeth in it? Que? Was? Quoi?

 

[Joe24]

Whut??? I don't understand ... you mean actually cut the solid metal, unbend it and put more teeth in it? Que? Was? Quoi?

Yeh.
Why not?

 

[Joe24]

Hacksaw it(or use a big **** off angle grinder!) then open it up, add another section in, and then weld that in place, or even do it so it can be bolted.

Simples.

Its not that solid.

 

[montage]

ignore joe

 

[Joe24]

ignore joe

bitch

 

[XmisterIS]

Lol! This thread is getting very surreal ...

...

... and back on topic please

Danke shoen.

 

[Joe24]

Just to come in and appologies!


As long as your cranks are already 130mm where the chainring goes, you should be ok.
Will need to move the front shifter up abit.
Will probably also need to have a new chain/add some links in.

Pointless though i think.

You will get 112 with 50/12
119 with 53/12
But you will get 122 if you have 50/11
Thats if you do actually have a 12 tooth on the back, and not an 11.
So, to wrap that up, to get a bigger gear, you could just put a smaller sprocket on your cassette/get a new cassette.

 

[Chris James]

What size is your cassette? If your smallest cog has 12 teeth you could increase your gearing by going for an 11 tooth, which would be a similar change to fitting a 56.

What speed are you going when you spin out your top gear? On an old bike I had a 48 front 14 back and could never spin out my top gear despite regularly getting up to 45 mph or so. Perhaps you just need to practice pedalling at a higher cadence?

 

[peanut]

just add a 11tooth sprocket and lock ring to your cassette and remove an unwanted sprocket like 14t
simples and cheap and easy you'll gain a huge 10"

50 x11 will be a bigger increase than using a 53 x 12

 

[XmisterIS]

What size is your cassette? If your smallest cog has 12 teeth you could increase your gearing by going for an 11 tooth, which would be a similar change to fitting a 56.

What speed are you going when you spin out your top gear? On an old bike I had a 48 front 14 back and could never spin out my top gear despite regularly getting up to 45 mph or so. Perhaps you just need to practice pedalling at a higher cadence?

I have a 12-25 cassette ... the 11-tooth solution makes perfect sense! Thanks Chris and peanut.

I am going at an indicated speed of about 40 mph when I spin out - and trust me, my legs are going like the clappers! Note the use of "indicated" ... I bought the cheapest speedo I could find! Sometimes it doesn't show any speed increase when I know full well that I am accelerating. When I spin out I am keeping up with cars.

 

[Joe24]

I have a 12-25 cassette ... the 11-tooth solution makes perfect sense! Thanks Chris and peanut.

I am going at an indicated speed of about 40 mph when I spin out - and trust me, my legs are going like the clappers! Note the use of "indicated" ... I bought the cheapest speedo I could find! Sometimes it doesn't show any speed increase when I know full well that I am accelerating. When I spin out I am keeping up with cars.

Not spinning fast enough, i can get up to 33mph on the flat on my 72" fixed, and do 41.7mph downhill on it.
If your doing 40mph downhill, just took down, you will go much faster.

 

[peanut]

two ways you could do this .
if you are rich and money no object simply buy a new cassette .
If you want to save some money try to buy a used 11-32 MTB cassette something like an XTR or Deore . Break the cassette up and use the 11 tooth and lockring .
The other sprockets could be useful in the future if you want to put say a 28t at the back of your cassette for hilly Audax .
Ribble Cycles or Chain Reaction are very reasonable
http://www.ribblecycles.co.uk/productdetail.asp?productcatalogue=SHIMCASS920

you don't say if you have 8 or 9 or 10 speed or if campag or Shimano cassette ? or which model 105 ultegra ?

 

[XmisterIS]

Yep, 10 speed Shimano 105. I don't fancy spending on a whole new cassette! I will look out for a 2nd hand one ...